1. Field of the Invention
The present invention concerns storage stable organic polyisocyanates. More particularly, the present invention relates to storage stable polyisocyanates characterized by allophanate linkages.
2. Prior Art
U.S. Pat. No. 3,769,318 teaches the preparation of allophanate containing polyisocyanates by reacting N-substituted carbonic acid esters with organic polyisocyanates in the presence of a compound having an alkylating effect. These alkylating compounds prevent trimerization side reactions. British patent No. 994,890 teaches the preparation of allophanate polyisocyanates employing metal or amine catalysts.